Ali KHALILI - Msc. in civil engineering, structural engineering, Tehran, I.R.Iran
Ebrahim EMAMI - Instructor, Payame Noor University, Tehran, I.R.Iran
Ali KHEYRODDIN - Professor, Semnan University, Semnan, I.R.Iran

One of the severe deficiencies in RC frame structures making it vulnerable against earthquakes is the inadequate shear resistance of beam-column joints and low stiffness of frames. To improve the seismic performance of the structure, improving the performance of its joints is essential. A steel curb and gusset plate system is introduced at the beam–column connections to protect the joint panel zone from extensive damage and brittle shear mechanisms, while inverting the hierarchy of strength and stiffness within the beam-column subassemblies and forming a plastic hinge in the beam. In this paper, the RC frames which were strengthened using this proposed method are investigatedunder monotonic lateral force using the numerical modelling. After verifying the models, local and global behavior of these frames, such as displacement, strength and ductility factor were studied. Analytical results show that maximum and ultimate lateral force of the strengthened frames has grown up to two times of the ordinary frame, averagely. According to the results, when the number of gusset plate increases, the strenght and stiffness of frames will increase remarkbaly but the ductility factor of frames will decrease relatively. The analytical results also demonstrated the effectiveness of the proposed solution for upgrading of RC frames and the displacing of plastic hinges to far from the beam-column joint.

Strengthening, RC Frames, Steel Gusset Plate and Curb, Finite Element